Algae are among the first organisms that appeared on Earth, and are defined as eukaryotic organisms that lack roots, stems and leaves, but that have chlorophyll and also other pigments that are incidental to oxygen-producing photosynthesis. They are blue, red, yellow, golden and brown or else green. They represent more than 90% of marine plants and 18% of the vegetable kingdom, with their 40 000 to 45 000 species. Algae are organisms that are extremely varied both in their size and their shape and in their cellular structure. They live in an aquatic or very wet environment. They contain numerous vitamins and trace elements and are real concentrates of active agents that are stimulating and beneficial for health and beauty. They have anti-inflammatory, moisturizing, demulcent, regenerating, firming and antiaging properties. They also have “technological” features which make it possible to provide texture to a food product. Indeed, the famous additives E400 to E407 are in fact compounds extracted from algae, the thickening, gelling, emulsifying and stabilizing properties of which are used.
Microalgae, in the strict sense, are microscopic algae. Either unicellular or multicellular, they are photosynthetic microorganisms divided into two polyphyletic groups: eukaryotes and prokaryotes. Living in highly aqueous media, they may have flagellar motility.
Chlorella is a freshwater microscopic unicellular alga that appeared on Earth more than three billion years ago. It was discovered in 1890 by a Dutch microbiologist Martinus Beijernick, who was fascinated by its chlorophyll content and by the presence of an element giving it a high multiplication rate: the CGF (chlorella growth factor). Chlorella has the highest concentration of chlorophyll of all plants and its capacity for photosynthesis is considerable. Since its discovery, Chlorella has continued to generate considerable interest worldwide and today it is produced on a large scale for uses in nutritional and food supplements. Indeed Chlorella contains more than 60% of proteins which contain many amino acids essential for human and animal well-being. Chlorella also contains a lot of vitamins (A, beta-carotene, B1: thiamine, B2: riboflavin, B3: niacin, B5: pantothenic acid, B6: pyridoxine, B9: folic acid, B12: cobalamin, vitamin C: ascorbic acid, vitamin E: tocopherol, vitamin K: phylloquinone), lutein (family of carotenoids, powerful antioxidant), and minerals including calcium, iron, phosphorus, manganese, potassium, copper and zinc. Moreover, chlorella contains certain omega-type polyunsaturated fatty acids essential for good cardiac and cerebral functions and for preventing numerous diseases such as cancer, diabetes or obesity. Chlorella has three elements that participate in its action:                the chlorophyll which is present in Chlorella at more than 4% (by weight) and is known for its purifying action.        the cell membrane: not digested by the human digestive tract which lacks the enzymes necessary for the degradation of cellulose, it fixes heavy metals and toxins and accelerates the elimination thereof by natural routes.        the CFG present at a level of 5% (by weight) is a powerful strengthening agent for the metabolism and for cell growth. It is an invaluable element originating from the nucleus of the cell and essentially containing amino acids, beta-glucans and nucleic acids. It gives chlorella a very rapid cell growth, multiplication and division rate.        
The benefits related to the consumption of chlorella are very numerous. It is a food supplement used daily in Japan by 4 million people. To such an extent that the Japanese government has classified it as a “food of national interest”. This precious alga is mainly, but not solely, recommended for:                calming the nervous system and promoting sleep;        reducing constipation, normalizing transit even in paralyzed people. It also restores the intestinal flora;        stimulating the immune system;        promoting acid-base balance;        stimulating cell regeneration and slowing down ageing;        decreasing the fats in the blood and reducing the risk of cardiovascular diseases;        reducing hypertension;        fixing heavy metals and other toxins, and eliminating them without damaging the liver; and        healing and allaying stomach ulcers.        
Document US 2004/0081665 describes the use of chlorella extracts containing high molecular weight polysaccharides and polysaccharide complexes possessing immunomodulating activity, which are intended to increase the production of cytokines and are used as components in the preparation of vaccines.
Document KR20030020767 describes a pharmaceutical preparation, possibly in the form of a tablet, a capsule or granules, for the prevention and treatment of osteoporosis, characterized in that it contains chlorella as active principle.
Document FR2747922 describes the use of concentrated extracts of chlorella-type algae for elaborating a product intended for preventing and treating skin diseases, characterized in that said extracts protect the Langerhans cells of the epidermis from ultraviolet radiation.
In the present invention, the word alga is used independently of the size of the algae, therefore including microalgae also. Preferably, they are microalgae.
No relevant document has been identified by the Applicant concerning the use of algae and/or extracts of algae in the prevention of oral-dental infections or diseases and/or for the upkeep of good oral-dental hygiene.
The best-known and most recognized method for maintaining good dental hygiene is regular brushing of the teeth and daily use of dental floss. However, these methods do not make it possible to prevent gingival inflammations and periodontal infections due to problems of inaccessibility of certain parts of the teeth or of the gums during brushing. Moreover, some people do not wish or do not have the opportunity to brush their teeth correctly and/or regularly. For example, certain situations may prevent an individual from maintaining good dental hygiene, such as illness or hospitalization. Other situations render brushing of the teeth difficult or impossible: inconvenience of locations, lack of hygiene, embarrassment, etc. In order to encourage oral-dental health, tests have been carried out in order to deliver active principles or medicines within the oral cavity, such as antiseptics, zinc salts, antibiotics, oxidants, folic acid, coenzyme Q10, etc.
Document WO 00/62762 describes sugar-free chewing gums with a therapeutic effect comprising a gum base, a soluble portion, a flavor, calcium carbonate and a food-grade acid, intended for remineralizing dental enamel and for preventing and treating dental caries.
Document US 2007/0110684 describes a method for treating and preventing dental problems through the use of an effective amount of Morinda citrifola, an Indian tree extract. The extracts of this plant may be in the form of a powder, a tablet, a chewing gum, granules, a toothpaste, a lotion for mouthwashes, in combination with other additives and/or active principles.
However, the effectiveness, the absorption, the metabolism, the bioavailability, the secondary effects, the regulation and the costs associated with these medicaments and/or active principles delivered into the oral cavity are some of the problems which it is necessary to overcome today.
Based on this observation, the Applicant has had the merit of discovering, surprisingly and unexpectedly, that the combination of the properties of a confectionery, and more particularly of a sugar-free confectionery, with that of microalgae and/or extracts of microalgae, and more particularly chlorella, made it possible to obtain a non-cariogenic confectionery having a beneficial effect for oral-dental health. Indeed this confectionery, and more particularly this sugar-free confectionery, combined with chlorella, provides a technically and economically viable solution to the prevention of oral-dental infections or diseases and/or to the upkeep of good oral-dental hygiene, enables simple use, under all circumstances and therefore promotes the maintenance of a healthy mouth throughout the day. Moreover, the use of a confectionery as a vector for Chlorella makes it possible to deliver the Chlorella directly to the site of oral infections and thus enables an optimization of the treatment, unlike the chlorella-containing supplements that currently exist and which must be swallowed directly. Indeed, it is difficult to imagine that the extracts of Chlorella contained in these supplements can have a beneficial action on oral-dental hygiene once they have reached the stomach. Furthermore, these supplements are not recognized or prescribed for the prevention of oral-dental infections or diseases and/or the upkeep of good oral-dental hygiene.
Moreover, the use of a confectionery as a vector enables simple use, at any moment of the day, with no particular constraint. The use of other means enabling good oral-dental health to be maintained, i.e. brushing the teeth and/or the use of mouthwashes after meals, specifically have the major disadvantage of not being able to be carried out simply, regularly and each time that the need therefore is felt.